theory and application of monitoring more than 20 iBeacon regions; as Core Location is limited to 20 regions, even the iOS Developer Library says, “to work around this limit, consider registering only those regions in the user’s immediate vicinity.”

On a recent project, we were using iBeacons and Core Location monitoring and ranging to track a user’s location in an indoor space. iBeacons are placed around the space and each iBeacon maps to a real world room or area like “conference room” and “entry area.”

We had a simplifying assumption that beacons, Core Location regions, and real-world regions have a one-to-one-to-one relationship. We were pretty happy with how well it was reporting locations with up to 20 beacon regions, but “Core Location limits to 20 the number of regions that may be simultaneously monitored by a single app.” So we needed to engineer a way around this limit in order to track more than 20 distinct locations in our system.

Read more: CoreLocation in the Wild: Experiments in Monitoring More than 20 iBeacon Regions